The invention relates to a method for producing a rotating electrical machine having an ironless coil, in the form of motors or generators having air gaps, in which the coil extends.
Such motors are referred to as air coil motors and have a high efficiency.
From the prior art various designs are known, on the one hand motors having bell-shaped coils and on the other hand motors wherein the armature coil completely surrounds the rotor. Within the armature coils, a freely rotatable permanent magnet is provided on a shaft, with the armature coil and the permanent magnet being coaxially supported.
From DE 20 2006 007 619 U1, a bell-shaped armature coil consisting of a hollow cylindrical coil wound using a winding wire is known, in the gap opening of which a coil carrier plate is single-endedly inserted. The bell-shaped armature coil forms the active part of the rotor and is formed as a self-supporting cylindrical coil having a helical winding.
Various methods are known for winding the bell-shaped armature coils.
One method provides for the winding of the coil to be carried out onto a sleeve or a mandrel. Winding is carried out successively in various layers, wherein after each layer, the wire is fixed by way of heating (intermediate baking). This is followed by winding the next layer, until the coil is finished. The final shaping process is carried out by way of the so-called finish baking. A further method consists in carrying out the entire winding process onto a sleeve or a mandrel, on the circumference of which distributed fine pins are provided at both ends, which pins fix the coil during the winding process. Winding is carried out continuously without intermediate baking. Subsequently, the pins are removed, the coil is withdrawn and the coil is finish-baked. A so-called self-bonding wire is used as a winding wire. Preferably, winding is carried out as a helical winding, which is easy to realise and has good self-supporting properties.
From DE 28 21 740 B2, a method for producing a bell coil is known, in which the coil is compacted after winding. To this end, an expanding mandrel or a pressure pad is used which acts outwardly in the radial direction onto the coil and presses the latter against an outer mould.
Disadvantages of these coils are on the one hand the relatively great ineffective conductor portion within each coil and on the other hand the skew extension of the conductor relative to the direction of movement.
A further disadvantage is that the effective conductor can be increased only by way of an axial extension of the machine. This will always have significant technical limitations, so that due to the high centrifugal forces in connection with the single-sided support of the coil, only relatively short bell-shaped armatures can be used.
From DE 101 37201 A1, an air gap coil with a bell shape within an electrical machine is known. This type of coil is an air gap coil with conductors that extend at least partially at an angle or in an arc shape relative to the direction of movement. The constructive form consists in the fact that the conductors are bent or folded in a targeted manner within a rotating machine in a cross-sectional view transversely to the direction of movement, and the coil approaches the axis or shaft in the axial direction at least on one side. The favourable geometric effects are then achieved as a result of the constructive form of the bending or folding as the coil approaches the axis, and by way of a targeted deformation of the conventional coil channel within the bent or folded shape of the coil.
From GB 95 46 23 A, a small direct current motor is further known, wherein the magnetic exciter field is generated by a permanent magnet provided within the armature, which is freely rotatable and is coaxially supported with the latter. The motor may for example consist of a coil support made from a tubular jacket having two front-side discs or two spaced-apart support discs, between which the coil itself is provided in a cantilevered manner. The coil is mounted on the winding support. The core magnet is rotatably supported inside the coil by way of a bearing on the rotor shaft. What is of disadvantage here, in the case of the cantilevered embodiment of the coil, is the relatively large air gap provided to prevent the coil from brushing against the core magnet or against the housing jacket.
From DE 694 07 908 T2, a method for producing a coil for an electric motor is known, wherein a winding wire is wound onto a support mandrel or alternatively onto a later rotor and is immediately fixed after winding. The windings can be pressed outwards in the radial direction in order to enhance the packing density. The pressing operation can be carried out in the magnet interference sleeve of the motor or prior to inserting it into the magnet interference sleeve in a separate device.
Proceeding from the prior art, it is the object of the invention to provide a method for producing rotating electrical machines having a cantilevered coil for motors or generators. This coil can act both as a rotor for an ironless air coil armature and as a stator fixed to an iron packet for generating an electric rotary field, and it should also be simple to produce from a technical point of view.